The twenty-four hours race around the Nürburgring, one of the world's most grueling courses.

"It's a conditioned response, triggered by only the most grueling of interrogations."

"My artificial body is able to withstand even the most grueling of tortures."

The year's final major tournament may end up being the most grueling.

It is the most grueling of the three major races, run over 4 miles and 22 jumps, some up to 5 feet high.

Being a graduate student is the most grueling and intense part of becoming a scientist, but it rarely leads to murder.

The marathon is among the most grueling athletic events known to man.

Granted, their recent schedule has not been the most grueling.

The first five days had been the most grueling.

Anybody involved with them worked under the most grueling of situations.